earths moon

not much water

There are no lakes, rivers, or even small puddles anywhere to be found on the Moons surface. So there is no running water and no atmosphere. This means that there is no erosion. Natural processes continually alter the Earths surface. Without these processes, our planets surface would be covered with meteorite craters just like the Moon. Many moons in our solar system have cratered surfaces. NASA scientists have discovered a large number of water molecules mixed in with lunar dirt. There is also surface water ice. Even though there is a very small amount of water, there is no atmosphere. Temperatures are extreme. So it comes as no surprise that there has not been evidence of life on the Moon.

lunar maria

When you look at the Moon from Earth, you notice dark and light areas. The maria are dark, solid, flat areas of lava. Maria covers around 16% of the Moons surface, mostly on the near side. The maria formed about 3.0 to 3.5 billion years ago, when the Moon was continually bombarded by meteorites (Figure 24.15). Large meteorites broke through the Moons newly formed surface. This caused magma to flow out and fill the craters. Scientists estimate volcanic activity on the Moon ended about 1.2 billion years ago. The lighter parts on the Moon are called terrae, or highlands (Figure 24.15). They are higher than the maria and include several high mountain ranges. The rock that makes up the highlands is lighter in color and crystallized more slowly than the maria. The rock looks light because it reflects more of the Suns light.

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interior of the moon

Like Earth, the Moon has a distinct crust, mantle, and core. The crust is composed of igneous rock. This rock is rich in the elements oxygen, silicon, magnesium, and aluminum. On the near side, the Moons crust is about 60 kilometers thick. On the far side, the crust is about 100 kilometers thick. The mantle is made of rock like Earths mantle. The Moon has a small metallic core, perhaps 600 to 800 kilometers in diameter. The composition of the core is probably mostly iron with some sulfur and nickel. We learned this both from the rock samples gathered by astronauts and from spacecraft sent to the Moon.

lunar characteristics

The Moon is Earths only natural satellite. The Moon is about one-fourth the size of Earth, 3,476 kilometers in diameter. Gravity on the Moon is only one-sixth as strong as it is on Earth. If you weigh 120 pounds on Earth, you would only weigh 20 pounds on the Moon. You can jump six times as high on the Moon as you can on Earth. The Moon makes no light of its own. Like every other body in the solar system, it only reflects light from the Sun. The Moon rotates on its axis once for every orbit it makes around the Earth. What does this mean? This means that the same side of the Moon always faces Earth. The side of the Moon that always faces Earth is called the near side. The side of the Moon that always faces away from Earth is called the far side (Figure 24.13). All people for all time have only seen the Moons near side. The far side has only been seen by spacecraft. The Moon has no atmosphere. With no atmosphere, the Moon is not protected from extreme temperatures. The average surface temperature during the day is approximately 107C (225F). Daytime temperatures can reach as high as 123C (253F). At night, the average temperature drops to -153C (-243F). The lowest temperatures measured are as low as -233C (-397F).

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lunar craters

The landscape of the Moon - its surface features - is very different from Earth. The lunar landscape is covered by craters caused by asteroid impacts (Figure 24.14). The craters are bowl-shaped basins on the Moons surface. Because the Moon has no water, wind, or weather, the craters remain unchanged. The Moons coldest temperatures are found deep in the craters. The coldest craters are at the south pole on the Moons far side, where the Sun never shines. These temperatures are amongst the coldest in our entire solar system.

the lunar surface

We all know what the Moon looks like. Its always looked the same during our lifetime. In fact, the Moon has looked the same to every person who has looked up at it for all time. Even the dinosaurs and trilobites, should they have looked up at it, would have seen the same thing. This is not true of Earth. Natural processes continually alter the Earths surface. Without these processes, would Earths surface resemble the Moons? Even though we cant see it from Earth, the Moon has changed recently too. Astronauts footprints are now on the Moon. They will remain unchanged for thousands of years, because there is no wind, rain, or living thing to disturb them. Only a falling meteorite could destroy them.

instructional diagrams

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questions

A total of six spaceships have landed on the moon.

-->  a. true

b. false

The flat dark areas on the Moon are

-->  a. lavas

b. dried lake beds

c. dried ocean basins

d. seawater

There are no current plans for returning to the moon.

-->  a. true

b. false

What are the lighter areas on the Moon?

a. maria

b. craters

c. lakes

-->  d. mountain ranges

The moons gravity is about half as strong as Earths gravity.

a. true

-->  b. false

What is the dominant feature on the lunar surface?

a. volcanoes

-->  b. craters

c. river basins

d. fault lines

The Moon has more extreme temperatures than Earth because it

a. is closer to the Sun

b. rotates faster on its axis

-->  c. doesnt have an atmosphere

d. has higher internal heat

It takes the moon the same amount of time to make one rotation as it does to make one revolution.

-->  a. true

b. false

The far side of the moon has been seen only from spacecraft.

-->  a. true

b. false

The interior structure of the Moon is

a. exactly like Earths

b. higher in metal

c. different on the near and far sides

-->  d. the same as Earths but with less core

Most lunar maria are on the far side of the moon.

a. true

-->  b. false

Natural processes continually alter the moons surface.

a. true

-->  b. false

Lunar highlands are made of light-colored rocks.

-->  a. true

b. false

There are rivers but no lakes on the moon.

a. true

-->  b. false

Astronauts brought moon rocks back to Earth.

-->  a. true

b. false

The Moon is Earths only natural satellite.

-->  a. true

b. false

Astronauts last visited the moon in

a. 1962.

-->  b. 1972.

c. 1982.

d. 1992.

Most of the maria are on the Moons near side.

-->  a. true

b. false

The moons size is

a. [U+215B] the size of Earth.

-->  b. 14 the size of Earth.

c. 12 the size of Earth.

d. 43 the size of Earth.

The surface of the moon always looks the same because the moon has no

a. gravity.

b. weather.

c. running water.

-->  d. two of the above

The lunar crust is thicker on the far side than on the near side.

-->  a. true

b. false

The coldest temperatures on the moon are found

a. deep in craters.

b. at the north pole.

c. where the sun never shines.

-->  d. two of the above

The Moon rotates on its axis once for every orbit it makes around the Sun.

a. true

-->  b. false

You would weigh six times as much on the Moon as on Earth.

a. true

-->  b. false

Which statement about lunar maria is false?

-->  a. They are still forming.

b. They look dark from Earth.

c. They formed billions of years ago.

d. They formed when magma filled craters.

Which of the following would you not expect to find on the moon?

a. ice

b. dirt

-->  c. bacteria

d. water molecules

You could find oxygen on the moon if you analyzed the

a. core.

-->  b. crust.

c. atmosphere.

d. none of the above

surface features of a moon or planet

a. lunar

b. maria

c. terrae

d. crater

-->  e. landscape

f. meteorites

g. asteroids

highlands on the moon

a. lunar

b. maria

-->  c. terrae

d. crater

e. landscape

f. meteorites

g. asteroids

cause of lunar craters

a. lunar

b. maria

c. terrae

d. crater

e. landscape

f. meteorites

-->  g. asteroids

related to the moon

-->  a. lunar

b. maria

c. terrae

d. crater

e. landscape

f. meteorites

g. asteroids

flat areas of lava on the moons surface

a. lunar

-->  b. maria

c. terrae

d. crater

e. landscape

f. meteorites

g. asteroids

bowl-shaped basin on the moons surface

a. lunar

b. maria

c. terrae

-->  d. crater

e. landscape

f. meteorites

g. asteroids

cause of lunar maria

a. lunar

b. maria

c. terrae

d. crater

e. landscape

-->  f. meteorites

g. asteroids

diagram questions

No diagram questions associated with this lesson